no pressure to the fuel rail?

Started the truck to go to the store, was sitting there and idling for maybe 2 minutes then it just stopped running. The gas gauge was showing low fuel, but not out sprayed. carburetor cleaner in the air horn the truck would fire so assumed that it was a fuel problem. I put 4 gallons of gas in it just in case no change. everything appears to be operational there's no pressure to the fuel rail with no fuel relay seems fine, fuse seems fine.